When rappers slip into freestyle mode — as opposed to using pre-existing lyrics — their brain activates a unique neural network that may enable creativity and improvisation.

Researchers from the National Institute on Deafness and Other Communication Disorders (NIDCD) at the National Institutes of Health (NIH) used MRIs to study the brain activity of 12 freestyle rap artists. (Interestingly, researchers used only performers who have been rapping for at least five years.)

The scientists scanned the rappers’ brains as they performed two different activities: 1) Improvising rhyming lyrics and rhythm patterns over a simple beat, and 2) rapping to rehearsed lyrics. Here’s what they discovered:

During freestyle rapping, the researchers observed increases in brain activity in the medial prefrontal cortex, a brain region responsible for motivation of thought and action, but decreased activity in dorsolateral prefrontal regions that normally play a supervisory or monitoring role. Like an experienced parent who knows when to lay down the law and when to look the other way, these shifts in brain function may facilitate the free expression of thoughts and words without the usual neural constraints.

That’s the state all performers aspire to; beyond thinking to just doing. The best jazz improvisers don’t say to themselves, “I think I’ll do a run up the minor scale now.” They just do the run up the minor scale. Or as the researchers put it, “Spontaneous improvisation is a complex cognitive process that shares features with what has been characterized as a ‘flow.'”

NIDCD’s researchers say that while the rappers were freestyling, brain activity increased in areas associated with language production and emotion, essentially forming a network of creativity and improvisation with the medial prefrontal cortex.